Not all casino bonus offers will allow you to "play through" the money on roulette. By that we mean the wagering requirements: if a casino is offering money for free, there will be some strings attached. You will need to make a certain amount of bets with the funds before you can withdraw any winnings (and sometimes before you can withdraw your initial deposit). Always read the small print first- if you are just playing roulette, it can be better to forego the bonus. If you are playing a mix of games, however, such as roulette, slots and say video poker then take the bonus.